As background, automatically operating injection devices may inject a predefined volume of a medicament into the body of a patient at predefined time intervals. This volume may be withdrawn from a reservoir, typically a replaceable ampoule, via a pump mechanism and may be injected through an injection needle or catheter placed in the patient's body. If an occlusion is present, the pressure in the injection system may increase, since there is no release of pressure provided by the injections. As a result, a force that is to be applied in the pump mechanism may increase over several unsuccessfully performed injections. A force measurement thus may make it possible to ascertain whether or not there is an occlusion. If an occlusion occurs, the patient may no longer be supplied with a necessary medicament. Moreover, since the pump unit may operate automatically at predefined time intervals, the pressure in the ampoule and in the feed lines to the patient's body may increase, which could cause damage to the injection device. An additional problem is that, with increasing pressure, the occlusion may suddenly dissipate causing the patient to receive too large a quantity of the medicament. By using a measurement unit that determines a force necessary for discharging the medicament, it may be possible to ascertain whether an occlusion is present.
Against this background, embodiments of the present disclosure are capable of quickly determining when an occlusion occurs in an injection device with a higher level of accuracy.